I have managed to pick up a horizontal warning scrollbar at the top of my screen with the letters moving along from right to left reading 'Warning! Your computer is infected! Press here for help!' Avast and CW Shredder have not been able to shift it so I wonder if anybody has experienced the same thing or managed to get rid of it successfully? Thanks.
The above file seems to be the problem, being a pf (prefetch file) which I have deleted from the Windows/prefetch folder but cannot delete from recycle bin for some reason. I get an error message when attempting to do this saying 'cannot delete file: cannot read from the source file or disk'.